P0079 Fault Code

P0079 OBD-II Trouble Code Short Description

Exhaust Valve Control Solenoid Circuit Low (Bank 1)

What does trouble code P0079 mean?

The P0079 fault code indicates a problem with the exhaust valve control solenoid circuit on bank 1 of the engine. This refers to a malfunction in the solenoid responsible for controlling the exhaust valve on the side of the engine numbered as bank 1 according to the vehicle manufacturer's cylinder numbering system.

In simple terms, the exhaust valve control solenoid plays a crucial role in managing the flow of exhaust gases through the exhaust system. It helps regulate the opening and closing of the exhaust valve, which directly affects the engine's performance and emissions.

When the P0079 code is triggered, it typically means that the voltage or resistance in the exhaust valve control solenoid circuit on bank 1 is below the expected range. This can be caused by various factors, including a faulty solenoid, damaged or corroded wiring, or a problem with the engine control module (ECM).

To diagnose and fix the issue, the following steps can be taken:

  1. First, a technician may use a scan tool to read the fault codes and gather any additional information stored in the ECM.

  2. They will then inspect the wiring and connections related to the exhaust valve control solenoid on bank 1. Any damaged or corroded wires will need to be repaired or replaced.

  3. Next, the solenoid itself will be tested to determine if it is functioning correctly. This can be done using a multimeter or by applying power directly to the solenoid and observing its response.

  4. If the solenoid is found to be faulty, it will need to be replaced with a new one. In some cases, the entire solenoid assembly may need to be replaced.

  5. Finally, after repairing or replacing any necessary components, the technician will clear the fault codes and test drive the vehicle to ensure that the issue has been resolved.

It is important to address the P0079 code promptly, as a malfunctioning exhaust valve control solenoid can affect engine performance, fuel efficiency, and emissions. If left unresolved, it may lead to further engine damage or other related problems.


What are the symptoms of the P0079 code?

The P0079 fault code refers to the Exhaust Valve Control Solenoid Circuit Low in Bank 1. Some common symptoms associated with this fault code are:

  • Check Engine Light is illuminated on the dashboard.
  • Decreased engine performance.
  • Engine misfires.
  • Rough idling.
  • Reduced fuel efficiency.
  • Poor acceleration.
  • Failed emissions test.

If you are experiencing any of these symptoms, it is advised to have your vehicle diagnosed and repaired by a qualified mechanic to avoid further damage to the engine.


What causes the P0079 code?

The P0079 fault code refers to the Exhaust Valve Control Solenoid Circuit Low on Bank 1. This code is set when the Engine Control Module (ECM) detects a low voltage signal coming from the exhaust valve control solenoid on the bank 1 side of the engine.

Possible causes for this fault code include:

  1. Faulty exhaust valve control solenoid: The solenoid may be stuck open or not functioning properly, causing a low voltage signal.

  2. Wiring issues: There may be a problem with the wiring harness or connectors associated with the exhaust valve control solenoid, leading to a low voltage reading.

  3. ECM malfunction: The ECM itself may have a fault, causing it to improperly read the voltage signal from the solenoid.

  4. Open or short circuit: There may be an open or short circuit somewhere in the circuitry of the exhaust valve control solenoid, resulting in a low voltage reading.

To diagnose and repair this fault code, it is recommended to perform the following steps:

  1. Check the wiring: Inspect the wiring harness and connectors for any signs of damage, corrosion, or loose connections. Repair or replace as necessary.

  2. Test the exhaust valve control solenoid: Use a multimeter to check the resistance and functionality of the solenoid. Replace if faulty.

  3. Check the ECM: Ensure that the ECM is functioning properly by performing diagnostic tests or consulting a professional.

By addressing these potential causes, you should be able to resolve the P0079 fault code related to the exhaust valve control solenoid circuit low on Bank 1.

Possible Solutions

How to fix P0079?

To fix the P0079 fault code on cars, you can follow these steps:

  1. Check the wiring: Inspect the wiring connected to the exhaust valve control solenoid. Look for any damage, loose connections, or corrosion. Repair or replace any faulty wiring.

  2. Check the solenoid: Test the exhaust valve control solenoid using a multimeter. Measure its resistance and compare it to the specifications provided by the manufacturer. If the resistance is out of range, replace the solenoid.

  3. Inspect the solenoid connector: Check the solenoid connector for any damage or corrosion. Clean the connector and make sure it is securely attached to the solenoid.

  4. Verify power and ground: Ensure that the exhaust valve control solenoid is receiving the proper power and ground signals. Use a voltmeter to test the voltage at the solenoid connector. If there is no power or ground, diagnose and repair the electrical circuit.

  5. Clear the fault code: After repairing any issues, clear the fault code using an OBD-II scanner or by disconnecting the battery for a few minutes. This will reset the vehicle's computer and allow you to see if the repair was successful.

  6. Test drive the vehicle: Take the vehicle for a test drive to ensure that the fault code does not reappear. If the code returns, further diagnosis may be required to determine the underlying cause of the issue.

Note: It is recommended to consult the vehicle's service manual or seek professional assistance for a more detailed and accurate diagnosis and repair process.